Treatment of cellulosic textile material



Patentedlamll, 1944 TREATMENT OF CELLULOSIC' TEXTILE TERIAL l Harold W.Stieglct, Stamford, and Linton A. Flnck, In, South Norwalk, Conn.,asslgnors to American Cyanamid Company, New York, N. Y., a corporationof Maine No Drawing.

Application August 30, 1941,

Serial No. 409.147

Claims.

This invention relates to the treatment of cellulosic textile materialswith methylated methylol-melamine. The invention includes the method oftreatment and the treated textile materials themselves.

We have found that cellulosic textile materials such as thread, yarn,and knit and woven cloth of cotton, linen, hemp, jute,.regeneratedcellulose, cellulose esters, cellulose ethers and other fibrousmaterials of cellulosic nature may be greatly improved in severalimportant characteristics by the application thereto of methylatedmethylolmelamine. Methylated methylol-melamine when applied tocellulosic textile fabrics in the amounts and in the manner hereinafterdescribed serves as a general finishing agent filling and weightin thefabrics and giving them a soft, springy hand. The fabric is also given afair degree of water repellency.

Another and more important result of our treatment of cellulosicfabrics. with methylated methylol-melamine is a resistance to shrinkingwhich is imparted to the fabric. We have found that cellulosic materialsof the type described above may be made substantially resistant toshrinking by the application of 2 to 8 per cent by weight of methylatedmethylol-melamine. The shrink resistance obtained as a result of ourtreatment may be illustrated as follows. Bleached cotton percale sampleswere impregnated with varying amounts of an aqueous dispersion ofmethylated methylol-melamine and the fabric tacked to its original size,dried and cured for 7 minutes at 284 F. The fabric sam-.

ples, together with an untreated control sample, were then washed forminutes at 160 F. .in a solution containing per cent soap and A per centsodium carbonate. Upon drying it was found that the untreated cottonpercale control sample had shrunk 4.4 per cent. The sample of the washedcloth containing'4 per cent of methylated methylol-melamine by weightbased on the dry weight of the fabric had shrunk only 1.1 per cent as aresult of the washing operation. Another cloth containing 3 per cent ofmethylated methylol-melamine was found to have shrunk only 1.7 per centand a cloth sample containing as little as 2 per cent of the methylatedmethylol-melamine had shrunk 2.5 per cent. Shrinkage measurements weremade along the warp of the cloth.

We have also discovered that when the amounts of methylatedmethylol-melamine added to the cloth is increased to values of the orderof 8 to 14 per cent by weight the cellulosic fabric in addition tohaving greater resistance to shrinking also possesses remarkableresistance to creasing. This is very surprising as it has heretoforebeen considered necessary to use as much as 30 per cent by weight ofother resinous materials to obtain the same degree of crease resistance.

In order to determine the permanency of the crease and shrink resistingproperties of our treated cellulosic fabrics samples of x 80 cottonpercale were impregnated with approximately 8 per cent by weight of themethylated'methylolmelamine. The fabric was then dried 3 minutes at 250F. and cured 4 minutes at 284 F. 3 /2 per cent of diammonium hydrogenphosphate by weight based on the'dry weight of the resin was added tothe resin dispersion as accelerator. The treated fabrics were washed ina standard washing machine for 4 hours at F. in a A P r cent soap and$4; per cent sodium carbonate detergent solution. Despite this drasticwashing the fabrics showed a resin retention of 87.3 per cent. Similartests made with other accelerators and difierent curing conditionsshowed comparable results.

One of the most important features of our new process is theunexpectedly low chlorine retention of the treated materials whensubjected to laundering operations involving bleaching steps. Many resinfinishes heretofore applied to cellulosic textile fabrics have had theserious disadvantage of picking up. chlorine from the bleach. Residualchlorine in the cloth causes considerable damage to the fabric when itis pressed or ironed. During the bleaching and while pressing the cloth,particularly when the pressing conditions are severe, part of thecellulose is converted to oxycellulose with the result that the fabricis weakened. The cloth also has a much greater tendency to turn yellowor scorch during pressing. Cotton percales treated with methylatedmethylol-melamine in accordance with our invention were tested forchlorine retention after the treated fabrics had been subjected tosevere washing and bleaching by commercial laundries. Results show asharply reduced tendency of the methylated methylol-melaminetreatedfabric to retain chlorine from bleaching baths as contrasted tothe behavior of other well known resinous textile finishing agents. Spottests for chlorine with starch-potassium iodide solution, pressing thefabric for 20 seconds on a fiat press set at its highest temperature(425-450" F.) and chemical analysis for oxycellulose as well astitrations for chlorine show conclusively that the chlorine retention ofour treated fabric was extremely small.

to those in the art; thus, for example, the dried. fabrics to'be treatedmay be immersed in the resin dispersion and then passed through suitablerolls as in a padder or mangle to secure uniform impregnation and toremove excessive resin. The fabric, however, may be impregnated by othermethods such as for example by spraying or with suitable boxes locatedon the mangle. Our invention is not limited to any particular method Themethylated methylol-melamine which we of impregnating the cellulosicfabric and other methods will of course occur to those skilled in theart.

As pointed out above the cellulosic fabrics may be renderedsubstantially resistant to shrinkage by the application of about 2 to 8per cent by weight of the resin based on the weight of the fabric.Larger amounts as for example 8 to 14 'per cent by weight of the resinwill not only shrink-proof the fabric but also impart thereto a highdegree of crease resistance. Accordingly our invention contemplates theapplication of 2 to 14 per cent by weight of methylated methylolmelamineto the cellulosic material.

After the material has been impregnated with the methylatedmethylol-melamine dispersion, or solution, it is dried and the resincured in the fabric by the application of elevated temperatures. Inorder to speed up the curing of the resin and decrease the heating timea suitable.

catalyst may be added to the aqueous resin dispersion. phosphate andmethyl acid pyrophosphate have given us particularly good results. Othercatalysts such as triethanol amine phthalate, zinc chloride, aceticacid, dilute mineral acids, as HCl, and others have been used withsatisfactory results. Still other catalysts for the curing of methylatedmethylol-melamine resins are known to chemists in the resin art and maybe employed.

The curing temperatures are in general quite low and may varyconsiderably from about 200 F. to about 300 F. with a correspondingreduction in time of cure with increase of temperature. The drying andcuring operation is flexible and may be varied to suit the equipmentavailable to the processor. High temperatures of the order of 280 F. to300 F. will cure the resin to a substantially water-insoluble state in 3or 4 minutes. Where facilities are not available for curing the resin atmoderate temperatures within the range of about 240 F. to 280 F., thefabric after impregnating with the desired amount of methylatedmethylol-melamine may be framed to width as on a pin ienter, dried,batched up on Oxalic acid, diammonium hydrogen v employ is prepared byknown methods. Two to six moles of formaldehyde is reacted with one moleof melamine to form a condensation product believed to be mostlymethylol-melamine. This product is then reacted with two to six moles ofmethanol whereby methylated methylol-melamine is formed. Excessivepolymerization should be avoided since the resin is preferably employedby us as'an aqueous dispersion, or solution, and products polymerizedexcessively tend to be dimcultly soluble in water. We have also foundthatexcessive polymerization of the product tends to give the cellulosicfabric a stiff hand.

What we claim is:

l. The process which comprises impregnating cellulosic textile materialswith 2 to 14 per cent by weight of a water-soluble methylatedmethylol-melamine in the form of an aqueous solution and thereafterdrying the textile material and curing the methylated methylol melaminewhereby it is rendered substantially water-insoluble.

2. The process which comprises impregnating cotton textile fabrics with2 to 14 per cent by weight of a water-soluble methylated methyloLmelamine in the form of an aqueous solution and thereafter drying thefabric and curing the methylated methylol melamine whereby it isrendered substantially water-insoluble.

3. The process of rendering cellulosic textile fabrics resistant toshrinking and creasing which comprises impregnating said fabrics with 8to 14 per cent by weight of a water-soluble methylated methylol-melaminein the form of an aqueous solution and thereafter drying the fabric andouring the methylated methylol melamine whereby it is renderedsubstantially water-insoluble.

4. The process of rendering cellulosic textile fabrics resistant toshrinking which comprises impregnating said fabrics with 2 to 8 per centby weight of a water-soluble methylated methylolmelamine in the form ofan aqueous solution and thereafter drying the fabric and curing themethylated methylol-melamine whereby it is rendered substantiallywater-insoluble.

5. A cellulosic textile fabric resistant to shrinking containing 2 to 14percent by weight of a heat-cured and substantially water-insolublemethylated methylol melamine, said fabric hav ing been impregnated withan aqueous solution of a. water-soluble methylated methylol melamine andthereafter dried and heated to cure the resin to a substantiallywater-insoluble condition.

HAROLD W. STIEGLER. IJNTON A. FLUCK, JR.

